fromPixels static method

Tensor fromPixels(List<int> pixels, int width, int height)

Create a tensor from RGB pixel values (not normalized).

pixels: flat array of RGB values R, G, B, R, G, B, ... in row-major order, values in range 0, 255 width: image width height: image height

Returns normalized tensor of shape (1, 3, height, width).

Implementation

static Tensor fromPixels(List<int> pixels, int width, int height) {
  assert(pixels.length == width * height * 3);
  final data = Float32List(3 * height * width);

  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      final srcIdx = (y * width + x) * 3;
      final dstIdx = y * width + x;

      final r = pixels[srcIdx] / 255.0;
      final g = pixels[srcIdx + 1] / 255.0;
      final b = pixels[srcIdx + 2] / 255.0;

      data[0 * height * width + dstIdx] = (r - mean[0]) / std[0];
      data[1 * height * width + dstIdx] = (g - mean[1]) / std[1];
      data[2 * height * width + dstIdx] = (b - mean[2]) / std[2];
    }
  }

  return Tensor(data, [1, 3, height, width]);
}